Jupiter's Great Red Spot is shrinking and could vanish within decades

Jupiter's Great Red Spot is the largest storm in the solar system — an anticyclone wide enough to swallow Earth whole. But it is also a storm in decline: careful measurements across more than a century show its long axis has been contracting steadily, and some researchers argue it may eventually break apart. ^[1][2]

The shrinkage is measured from Earth, which is part of the difficulty. The spot sits in Jupiter's southern hemisphere and rotates with the planet roughly every 10 hours, so observers rely on its oval outline against the cloud tops. Historical drawings and telescopic records from the 19th century put its length near 40,000 km; modern images from telescopes and passing spacecraft place it closer to 14,000 km. ^[1][2][3]

Why a shrinking storm might not simply fade away

Vortices in a fluid lose energy to turbulence and to the surrounding jets. As the Great Red Spot contracts, it has also been growing rounder — its aspect ratio is becoming more circular rather than staying a stretched oval. A rounder vortex can be more stable in some regimes, so 'shrinking' does not automatically mean 'dying soon.' ^[2][3]

• Its winds still reach hundreds of kilometres per hour, so it remains a powerful storm despite the smaller footprint. ^[2]
• Smaller, paler anticyclones have been observed forming and merging with the spot, which can feed or disturb it. ^[3]
• Long-term records are sparse and inconsistent: different observers measured different cloud features and used different methods. ^[1][2]

What we can and cannot predict

There is no consensus date for the spot's disappearance. Extrapolating the current trend suggests it could become circular within decades, but fluid dynamics on a giant planet is not a straight line, and past behaviour has surprised observers. NASA's Juno spacecraft, in orbit since 2016, has been studying the storm's depth and winds to understand what keeps it alive. ^[3][4]

For now, the honest answer is that the Great Red Spot is clearly smaller than it was, and it may keep shrinking — but 'could vanish within decades' is a projection, not a scheduled event. ^[1][4]